A gunman killed during a police raid on an apartment in northern Cairo is suspected of involvement in a deadly attack last month on the US consulate in the Libyan city of Benghazi, police said Thursday.

Various media reports meanwhile suggested that the man who died in Wednesday's raid was a Libyan citizen who is believed to be an Al-Qaeda militant.

"The gunmen who was killed when police raided an apartment in Madinat Nasr... is suspected of having connections with the group that carried out the attack on the US consulate in Benghazi," an Egyptian police official said.

US ambassador Christopher Stevens and three other Americans were killed in the September 11 attack on the US consulate in the eastern Libya city.

At the time, social networks blamed the hardline Salafist group Ansar al-Sharia for the attack.

The independent Al-Masry al-Youm newspaper, quoting interior ministry official General Mohieddin al-Sayyed, said the suspect killed on Wednesday could be an Al-Qaeda militant.

"The Madinat Nasr police department received information indicating that a terrorist, a member of Al-Qaeda, was present in an apartment in Madinat Nasr," Sayyed is quoted as saying.

As a result police raided the apartment and clashed with the suspect who was killed when he activated an explosive device, he said.

Another independent newspaper, Al-Watan, reported that the suspect was a Libyan citizen.

Without giving a source, it said that security services had additionally "arrested a seven-member terrorist cell in Cairo, five of whom are Libyans and the other two Egyptians." The state-owned Al-Gomhoriya newspaper quoted Interior Minister Ahmad Gamal confirming "the arrest of a terrorist group" who had used flats in Madinat Nasr and in eastern Cairo "to store weapons, ammunition, bombs and explosives." Police had on Wednesday said the suspect was killed in an explosion during the raid on the Madinat Nasr apartment.

Police acted on a tip-off that a militant was hiding out in the apartment, which he had converted into a gym, but when agents tried to enter it they came under fire.

Police found a number of rocket-propelled grenades and three rifles inside, a police official said.

Egypt's police force has been conducting sweeping operations against heavily armed criminals nationwide and also Islamist militants in the Sinai peninsula.